Abstract:

Combined with special structure of tunnel and wireless signal transmission characteristics, and analysis of electromagnetic wave polarization,the paper present the measurements of wireless communication in tunnel,the height of tunnel is 3 m and the width of tunnel is 2 m, the testing frequency is 433 MHz, transmit power is from -30 dBm to -25 dBm, receive sensitivity is -105 dBm, the gain of linear polarization antenna is 2 dBi, the transform data is not coding. Through theoretical analysis on electromagnetic wave polarization and measurements, rectangular tunnel height is H and width is W, when H＞W, the vertical polarization mode is better than horizontal polarization; when H＜W, horizontal polarization mode is better than vertical polarization.

Key words: vertical polarization, horizontal polarization, reflection wave, transmission wave, tunnel